Posts Tagged 'ornithischian'

My new paper is out today and it describes a wonderful new specimen of four baby Protoceratops together in a single block. Unlike many other groups of exceptionally preserved specimens from the Mongolian Gobi, the animals are effectively stacked on top of one another and all facing in different directions and importantly, their inferred age is different to other Proto specimens.

This specimen was actually collected in the early 1990s, something I hadn’t realised when I saw it in 2011 in the Hayashibara museum in Japan. This was my second trip to the museum after having been in 2009 (that led to the Tarbosaurus bite marks paper) and this was the specimen that really grabbed me and I am obviously most grateful to co-author Mahito Watabe for allowing me to lead the paper on this.

The preservation is superb, and although there’s been some erosion and damage (especially to the uppermost animal) at least one of them is brilliantly exposed and almost immaculate in condition. At this point I must praise the preparator for his incredible work here, this is a huge block (close to a metre cubed), the matrix is exceptionally soft and brittle and the organisation of the specimens must have made the whole process extremely difficult and the result is both beautiful and impressive.

There are two major aspects to the paper (which is in PLOS ONE so for all the details and tons of pics so you can read it all there) and I’ll deal with them in separate posts. The first one is the block itself and the implications for Protoceratops generally. There are a number of groups of this dinosaur known already – several sets of adults, a pair of subadults (also briefly covered in the paper – and shown below) and a set of very young animals that were described a few years ago as something close to hatchlings in a nest. In the paper we actually suggest that these were not in a nest, but free living, but the wider point is that we have similar sized animals (that are probably of a similar or the same cohort) together at multiple different life stages, and we don’t seem to see mixed cohorts as with many other dinosaurs.

The block here slots into this pattern beautifully, the animals are about twice the length of the smallest ones, and about half the size of the subadults. That means we can put together a sequence of specimens at four pretty distinct life stages where we have groups of animals together at different times of their lives. That is something we have not been able to do for any extinct dinosaurs before – we do often have groups together and often of adults or juveniles or the two mixed together, but we are not aware of a so many obviously different cohorts of a single species showing this. Wonderfully, these are not all just Protoceratops, but all P. andrewsi and even better all of these are from a relatively narrow time and space window.

As non-avian dinosaurs go, that’s about as close to a single population as you are really going to be able to find, so collectively we are inferring that this was a pretty normal behaviour for this population. That sounds like a pretty conservative approach (can we not apply it to the genus or species as a whole?), but I think it’s something we really need to do a lot more of in palaeontology. The sheer variety and plasticity of many behaviours, especially when it comes to forming groups, means that is probably dangerous to extrapolate without some good supporting evidence and that sets things up quite nicely for the second post which will follow tomorrow.

Sadly I have to report that after many years working on various diapsids and having published plenty of papers on dinosaurs generally and theropods specifically, and yes even sauropods, I’ve gone and published two papers on ornithischians. I hang my head in shame, obviously, and I hope too many readers won’t think too little of me (though I doubt Tom Holtz will ever return my calls now). The first is on the wonderful Protoceratops and delves deep into dinosaur behaviour (and should be out on Wednesday), but this time it’s the monstrous hadrosaur Shantungosaurus, which has not really had anything like enough attention given just how much material is floating around.

The paper is a chapter in the new ‘Hadrosaurs’ volume that has been long in the making (and indeed publishing, since it as basically done a year ago) and if at this point effectively out. Actually I’m not sure quite how available things are, but the volume has appeared on Google Books (with the incorrect date of 2015 on it) and copies are apparently in mail, plus at least some coverage of various chapters is already out. As a result, I don’t think I’m jumping any particular embargo. though I appreciate not everyone may be able to read it in the next few days. Anyway, onto colossal hadrosaurs.

After the initial excavations of the 1960s, not much happened in the quarries where the remains of Shantungosaurus were first found. It was identified as a giant hadrosaur, plenty of isolated remains were collected and distributed to various collections and then, well, not much. The new digs over the last decade or so have seen a raft of new finds, but all the attention has really been on the other things coming out of the quarries, namely the new tyrannosaurs, ceratopsians and other beasties. That’s a shame as there are literally thousands of elements available to study and these are coming out in multiple quarries.

Over several visits, my good friend and longtime collaborator Corwin Sullivan and I went over the largest of the three main sites at Zhucheng, the Kugou Quarry, and took note of every bone that we could find and identify. The quarry maxes out at some 300 by 30 m, so it’s truly giant, and both ends are missing thanks to the erosion of the hill and it’s not clear how deep it might be. We also could not access every part of it safely and thus although we noted some 3000 elements, we estimate there are closer to 5000 exposed, and there could be huge numbers still to find. Out of these, barely a handful belonged to anything other than Shantungosaurus – a tyrannosaur tooth, a couple of tyrannosaur bones, a croc osteoderm and a bit of turtle. (And, oddly the near complete and articulated Zhuchengceratops, though I suspect it is from a different horizon). In short, this entire area and material essentially represents just one genus and probably a single aggregation.

All the material is essentially disarticulated and while basically every part of the skeleton is there, it is horribly jumbled. There’s no evidence of scavenging or trampling, and little sorting either, so this looks like a pretty major event that led to a rapid burial of the remains. We don’t dwell on what might have done this, but bearing in mind the size of these animals and how many there were and this is clearly something big, and also probably quick (this is not a long term accumulation of material).

Already 5000 elements is quite a bit, but the bones are also big. Shantungosaurus is well known as being a really large hadrosaur, but more than that, it’s absolutely colossal. While femur length is not the best size proxy out there, neither is it that bad, and was the only thing we could reliably measure for large numbers of the elements preserved that would give a decent size estimate. The largest femur we could accurately measure was 172 cm long – bigger than the largest specimens of Diplodocus and comparable to many big sauropods like Apatosaurus and Antarctosaurus. While they do have very different builds as animals, don’t forget that hadrosaurs were not pneumatic, so it’s quite reasonable that these animals had similar masses to those huge sauropods. Similarly that also means that perhaps many sauropods were not as heavy as the largest hadrosaurs which does have implications for how we look at things like the reasons sauropods did get so large. Mass estimates that are available or can be calculated for Shantungosaurs are extremely varied and this is perhaps due to it being so much larger than anything else known when it comes to hadrosaurs or even other ornithischians. Is is basically off the charts (few ornithischians have femora that exceed 1 m in length, and the smallest specimens we measured were bigger than this) and it probably needs to be tackled with a specific rigorous analysis to get a good estimate. Still, I’d be very surprised if the larger individuals were under 10 tons, and it is probably the heaviest ornithischian known and by extension, probably the heaviest terrestrial biped, since I didn’t see anything in the available material to suggest it could not walk bipedally.

Femora were also measured as they are large elements that are relatively easy to identify correctly and were in relatively decent condition, and so go some way to determining a minimum number of animals in the quarry. We counted 110 and so there is a minimum of 55 animals here, and I would be stunned if there were not very considerably more than that in reality (or indeed many more femora in there that are simply not exposed). But any measure then, this is a lot of animal – over 50 individuals, the smallest of which had a femur over 1 m long, and many of which were large sauropod sized. Indeed, the distribution of the femora actually tells us something too.

The range of sizes seen is actually really narrow: almost 85% of them fall between 135 and 175 cm and aside from three small ones that were little more than a meter, the rest form an almost perfect normal distribution. In short, this looks like a natural population of adult animals and we can infer they are adult both on the general size and the fact that all the elements of things like sacra in the quarry were fully fused. It has been suggested before that hadrosaurs form separate groups and that adults may have aggregated without juveniles, and with juvies and /or subadults forming separate groups, and that fits well with what we see here (and this also fits with the ideas covered in the forthcoming Protoceratops paper).

Collectively then the remains from this quarry do look something close to a natural aggregation, representing a pretty massive accumulation of biomass (over 50 animals and likely closer to 100, and probably over 10 tons each). It’s hard not to think about just what this means for a Mesozoic landscape, even a big Zhuchengtyrannus would be pretty much outclassed by one of these, let alone dozens together, and they would presumably have been able to strip huge swathes of vegetation clear as they foraged. For me at least it’s a nice evocative image, though perhaps not a long lasting one given that something massive rather dismembered and buried them shortly afterwards. Happily for palaeontologists we have now found this graveyard and there’s a massive amount of material available on these massive dinosaurs, and I hope that there is much more to come now that it is becoming available for study.

While I’m sure huge parts of the internet are currently going mad over the new ornithischian Kulindadromeus and the implications for fuzzy dinosaurs (or otherwise) there current crop of pictures available isn’t that great. Inevitably those in the paper are small and crammed into the limited space (in the main paper at least, I’ve not yet got hold of the supplementary files and am writing this before the paper is released) and the press images are focused on the beautiful life reconstructions. However, Pascal Godefroit was kind enough to pass onto me a pile of images that he said I could use. Many have made their way onto my Guardian piece on the subject, but even there they have to stay small to fit the website’s style and some of the detail is lacking, so I’ll put them up here instead.

Obviously these images come directly from Pascal and are copyright to him and his team and should not be reproduced without his direct permission. Anyway, they do show some nice details of various parts of these specimens and the different integumentary structures (both scales and filaments) rather well and I imagine will be of some interest. I won’t add any more description here since I’ve already written a couple of thousand words on this animal today and I suspect most readers will be angling for the paper to do their detailed reading anyway. Enjoy.

Multiple filaments associated with the femur

Multiple filaments associated with the humerus.

Small scales associated with the pes.

Small filaments associated with the skull.

Filaments at the proximal tibia.

Scales on the distal tibia.

Close up of tooth series.

Huge thanks to Pascal for lending me these images and letting me put them online and obviously my congratulations on the discovery.

By now most people with even a passing interest will be aware of the fact that there are now a number of specimens (and indeed species) of ornithischian dinosaurs that are preserved with some form of filament-type structure which, superficially at least, bear some resemblance to primitive feathers. However when the first candidate was announced, this specimen of Psittacosaurus housed in Frankfurt, it inevitably causes something of a furore with many suspicious of the data and suggestions that the filaments were simply coincidentally preserved plant stems or something similar.

The discovery of multiple specimens of Tianyulong inevitably make this rather more plausible as a real find, though of course a few more filamented Psittacosaurus would be nice. A third taxon is apparently now know but sadly illness led to a no-show at SVP so few have seen anything of this new find. Still, the original find is an impressive specimen, but doesn’t seem to have really been thoroughly described or illustrated too well and as I’m in a position to at least partially rectify that, here’s some photos I took of the specimen on my recent trip.

I have actually seen this before years ago but extremely briefly, and have also seen a superb cast of it in the Carnegie (my photo of which actually popped up in a dinosaur text book recently, [with permission I should add] such was the quality of the copy). However, I’d never really *looked* at it properly and actually spending a few minutes (even through a glass case) reveals some lovely details.

First off, it’s big. The biggest specimen I’ve seen by far for this genus, though the head is not that large compared to the rest of the body. Then there is skin pretty much everywhere – this does turn up in Liaoning not too infrequently, but rarely to this extent or quality. It covers large chunks of the animal and even completely covers large chunks of the bones in places (just look at the femur) and it looks like there’s a pile of gastroliths in the gut that are also covered.

While I’d be very cautious about interpreting the extent of the skin as being directly linked to other soft tissues, the extensive ‘flap’ behind the hindlimb would correspond with what you might expect from large retractor muscles there and so might well be genuine. Not only that, but there’s quite a bit of texture to the skin and in a couple of places it appears to have a different surface texture to others (see the underside of the base of the tail, and the area around the toes), which could also be genuine. On top of that, both the individual scales are clear in some places, and are even coloured differently (the larger ones are black) implying at least the possibility of this representing a pattern on the animal, and this changes along the body (look a the concentration in the tail, compared to the legs) though again:caution. It does look rather like this little patch that I featured years ago which is rather neat. Finally, this pattern also extend onto bones that are not obviously covered with skin (see the distal forelimb for example) with apparently the stains or some other taphonomic artefact of the scales left on the bones themselves.

And yes, then there are the filaments. Sprouting up off the base of the tail and extending most of the way along its (incomplete) length. They are rather thick and clearly somewhat stiff, but also flexible enough to bend under their own weight. While not a common reference, they look a lot to me in terms of their apparent properties like the tail hairs of giraffe (though much, thicker). It’s a real shame they are at least in part cut off the edge of the slab, but certainly appear to have stopped appearing well short of the end of the tail, so their full extent does appear to have been preserved.

I think that’s everything I can reasonably (or even unreasonably) speculate about this specimen without, yknow, actually going back and reading the original paper and associated commentary. However, the really key thing is of course that here’s some nice pictures of this and it gives a welcome opportunity to revisit this important and interest specimen.

Well the new ceratopsian Nasutoceratops has been named and the paper is out. If you want to read a bit about it, I have a post up over on the Guardian here. Since that’s already written, I wanted to do something a bit different here and thanks to Mark Loewen, I’ve been supplied with a series of nice images and art of the beastie and it’d be a shame not to use them here.

Here’s Lukas Panzarin’s skeletal of the animal (note that most of the skull is known).

Here’s Samantha Zimmerman’s lovely scientific illustration of the skull in two views which really shows off the shape and pattern of the horns well.

Lukas Panzarin is back again with this life reconstruction of the head.

Next we have a Raul Martin piece of the whole animal, making its way through a swamp.

And finally Andrey Atuchin’s effort, another life reconstruction, this time with a nice tyrannosaur half hidden in the background.

All in all some beautiful stuff, but I had no room for it on the Lost Worlds, so I’m pleased to get it up somewhere. Thanks to the team for sharing and great stuff from all the artists.

This place is going to be Theropod Central for a bit (until the huge volume of ceratopsians kick in), so here’s an ankylosaur to keep things ticking over. As usual, enthralled though I was with the exhibitions, I didn’t pay that much attention to the various signs or details of some of what I was looking at. As a result I don’t know all the identifications exactly and when it comes to things like these guys, well it’s hardly my best subject either.

Happily however, Victoria Arbour has just published a monster paper with Phil Currie on the taxonomy and identity of North American ankylosaurs and is also furiously blogging about it. So hop on over to her blog and start reading up on them. Handily there’s guides to the various parts of the skulls and rings of armour on the neck too which will really help out here. So while I’m obviously being too lazy to look it up myself, I’ll claim I’m inspiring readers to learn how to do it themselves.

Late edit: Victoria has joined in the comments to point out this is a nodosaur, and thus not in her review. D’oh. Still, go read her series anyway, it’s ace, and look at the pretty nodosaur skull (also ace). It is Edmontonia.

Trawling through a few more of my photos from Tokyo turned up a few more things I never got round to covering. Among them is this little seen hadrosaur – Nipponosaurus. This is one of the few dinosaurs known from Japan (though the number is creeping up slowly with even a sauropod having been described recently) and as far as I’m aware is known from just the one specimen, an incomplete juvenile (though with a skull) which formed the basis of this rather nice mount.

I’m not quite out of Canegie photos yet, so here are the mounted Ceratosaurus and Dryosaurus. My first of either and while it is cool to see a young Ceratosaurus (I simply didn’t know there were specimens of animals this size) I must confess I had hoped to see an adult Allosaurus-sized individual. Still these are both classic Morrison taxa and added still more to my ‘first time’ list of species that I got from this trip to the U.S.

While I’m clearing out old photo albums, here’s a cast of the Lambeosaurus head. Well, I rather assume it is, I’m not that familiar with the more obscure hadrosaurian crests and this does look about half-way between a Corythosaurus and Lambeosaurus. A quick skim of Lull & Wright suggests it’s more like L. magnicristatus than anything else, but it’s still not *quite* right for that either.

It’s held in the basement at Eichstaett and they don’t seem to know where it’s from beyond ‘Canada’ or which specimen it’s based on / taxon it’s supposed to be. Anyway, it is a nice one and something I’ve not seen before (perhaps no surprise given the paucity of hadrosaur mounts in Europe) and lacking anything else to go up till New Year it’ll have to do!

Ah the boneheaded dinosaurs. I’ve only ever covered these a couple of times as there are few mounts of them in museums and (hugely convoluted and problematic taxonomy aside) there’s not that much to talk about. Did they or didn’t they fight and in which manner has been done to death but there’s really not that much beyond this – after all their fossil record is actually pretty poor aside from the thick skull-caps and here are few specimens which border on even partially complete. SO you’ll just have to settle this time around for yet another mount from the Carnegie.

A couple of months back I posted this on the display of ceratopsian skulls in Tokyo and lamented that they looked great, but were several meters off the ground and thus their position was rather sub-optimal. What’s especially nice with the Carengie’s version is not only that these were nice and accessible, but are all different species to those in Tokyo so between the two, it’s quite a collection. Here then are are Carnegie heads: